Safety switch

Abstract

A safety switch includes a switch housing having at least one key channel into which a key can be introduced from the exterior. A plate cam projects into key channel and rotates when the key is introduced. A mechanism in secures the plate cam when the key has been fully introduced or completely removed.

What is claimed is: 
     
       1. A safety switch, comprising: a switch housing:   a first key passage in said switch housing;   a key receivable in said key passage from a location exterior of said switch housing;   a plate cam projecting into said key passage and rotable in said switch housing about a rotational axis upon introduction of said key; and   securing means in said switch housing for securing said plate cam against rotation when said key is completely introduced into said key passage, and for allowing said key to be introduced deeper into said key passage after said plate cam is secured by said securing means.   
     
     
       2. A safety switch according to claim 1 wherein said securing means secures said plate cam when said key is not introduced into said switch housing.   
     
     
       3. A safety switch according to claim 1 wherein said securing means comprises at least one recess and a cooperating blocking element movable relative to said plate cam.   
     
     
       4. A safety switch according to claim 3 wherein said blocking element is movable in a radial direction relative to said rotational axis, and is spring biased against said plate cam.   
     
     
       5. A safety switch according to claim 4 wherein said at least one recess is provided in one side of a shaped material part on said plate cam; and   an interlocking member is arranged on one side of said plate cam and includes said blocking element.   
     
     
       6. A safety switch according to claim 5 wherein said interlocking member comprises an oblong-shaped opening surrounding said rotational axis of said cam plate.   
     
     
       7. A safety switch according to claim 6 wherein said interlocking member is movable perpendicular to said rotational axis of said plate cam.   
     
     
       8. A safety switch according to claim 3 wherein said at least one recess is provided in one side of a shaped material part on said plate cam; and   an interlocking member is arranged on one side of said plate cam and includes said blocking element.   
     
     
       9. A safety switch according to claim 8 wherein said interlocking member comprises an oblong-shaped opening surrounding said rotational axis of said cam plate.   
     
     
       10. A safety switch according to claim 9 wherein said interlocking member is movable perpendicular to said rotational axis of said plate cam.   
     
     
       11. A safety switch according to claim 3 wherein said at least one recess is provided in an area of said plate cam projecting into said key passage during rotation of said plate cam; and   said blocking element is provided on said key.   
     
     
       12. A safety switch according to claim 11 wherein said at least one recess is configured as a groove; and   said key is fork-shaped with a longitudinal slot, said blocking element being formed by recessed cut-out sections on an interior of said longitudinal slot.   
     
     
       13. A safety switch according to claim 1 wherein said securing means are symmetrically provided on both sides of said plate cam.   
     
     
       14. A safety switch according to claim 1 wherein a second key passage extends in said switch housing non-parallel to said first key passage; and   an operation member is movable along an angle bisecting said first and second key passages, and projects into said first and second key passages when said key is not introduced into one of said key passages.   
     
     
       15. A safety switch according to claim 14 wherein said operation member is part of an interlocking member.